Process for selectively deforming a thermoplastic layer

ABSTRACT

This invention relates to the process for deforming a thermoplastic layer by forming an electrostatic image thereon and heating it, the improvement which comprises effecting deformation in a part of the layer only, and effecting the heating by a dry thermal treatment.

United States Patent Sch'zidlich et al.

[ 1 July 29, 1975 PROCESS FOR SELECTIVELY DEFORMING A THERMOPLASTICLAYER Inventors: Giinther Schiidlich, Wiesbaden;

Roland Moraw, Naurod ub. Wiesbaden, both of Germany Assignee: I-IoechstAktiengesellschaft,

Germany Filed: Sept. 5, 1973 App]. No.: 394,414

Related U.S. Application Data Continuation of Ser. No. 206,604, Dec. 10,1971, abandoned.

Foreign Application Priority Data References Cited UNITED STATES PATENTS7/1965 Mihajlov et al 96/1.l

3,196,012 7/1965 Clark 96/l.1 X 3,245,053 4/1966 Brown et al. 96/1.1 X3,262,122 7/1966 Fleisher et al. 96/1.1 3,284,196 11/1966 Mazza 96/1.l3,328,776 6/1967 Hughes et a1. 96/1.1 X 3,413,146 11/1968 Anderson eta1. 96/1,1 X 3,526,879 9/1970 Gundlach et al. 96/1.l X 3,801,314 4/1974Goffe 96/1.1 X

FOREIGN PATENTS OR APPLICATIONS 581,917 0000 Belgium 96/1.1

OTHER PUBLICATIONS Glenn, Thermoplastic Recording, Journal of AppliedPhysics, Vol. 30, No. 12, Dec. 1959, pp. 1870-1873.

Primary ExaminerNorman G. Torchin Assistant ExaminerJohn R. MillerAttorney, Agent, or FirmJames E. Bryan [57] ABSTRACT This inventionrelates to the process for deforming a thermoplastic layer by forming anelectrostatic image thereon and heating it, the improvement whichcomprises effecting deformation in a part of the layer only, andeffecting the heating by a dry thermal treatment.

8 Claims, 11 Drawing Figures PATENTEDJULZQIBYS 3, 897, 2-47 sum 1PATENTED JUL 2 9 I975 SHEET PATENTED JUL 2 9 I975 SHEET PROCESS FORSELECTIVELY DEFORMING A THERMOPLASTIC LAYER This is a continuation ofapplication Ser. No. 206,604, filed Dec. 10, l97l, now abandoned.

PROCESS AND APPARATUS FOR DEFORMING A THERMOPLASTIC LAYER This inventionrelates to a process for deforming a thermoplastic, preferablyphotoconductive layer suitable for recording a deformation image orcontaining such an image, by electrostatic, if desired image-wisecharging, followed either by image-wise exposure and heating, or byheating alone, and to an apparatus suitable for performing the process.

Processes for the preparation of deformation images byelectrophotographic means are known. The recording material comprisessupport of dielectric, possibly transparent material, e.g. plastic filmor glass, which may be provided with an electrically conductive layer oftin oxide, aluminum or the like, or of an electrocon ductive supportingmaterial, e.g. an aluminum foil. On this support, there is a layer of athermoplastic resin, preferably mixed with photoconductive substances,or these substances may be in a separate layer. The surface of thematerial may be provided with an electrically non-conductive layer whichalters the reflection of light. The electrophotographic recordingmaterial is electrostatically charged under a corona device, image wiseexposed, and then softened. During softening, the surface of theplasticized resin becomes deformed under the influence of the latentcharge image and forms a deformation image. Different kinds ofdeformation images are obtained, depending on the electrostatic charge.In the case of a relatively high charge, the surface of the chargedareas assumes an irregular structure, so that an image produced by lightscattering is formed which can be viewed or projected (frost image). lfthe material is charged to a lower potential, a

continuous relief line is produced on the otherwise smooth background,which line marks the boundary where there is a discontinuity in themagnitude of the charge, caused by image-wise exposure (photoplasticrecording). The relief images produced are viewed through a phasecontrast microscope or made visible by means of a Schlieren opticalsystem.

Softening of the layer provided with a charge image may be effected bytreatment with solvent vapors or by immersion in a solvent.Alternatively, it may be effected by the application of heat, e.g. byimmersion in a warm dielectric liquid. Frequently, the heat energyrequired for development is supplied by irradiation. By the sametechnique, the deformation image produced may be erased by softening.

ln the known processes, the recorded original is reproduced as a whole.This has the disadvantage that in the case of a faulty composition oforiginals, the whole image has to be deleted by the softening proceduredescribed. So far, it has not been possible to effect a partialdeformation, i.e. to correct signal lines or points, or to complete thedesired information or delete undesired information. Further, it has notbeen possible hitherto to gradually change the recorded information atdifferent points of time. However, such techniques are of greatimportance for modern systems of information.

The present invention provides a process for producing or erasing adeformation image within a very narrow zone and at different points oftime.

This is achieved by a process for deforming a thermoplastic, preferablyphoto-conductive layer suitable for recording a deformation image orcontaining such image, by electrostatic, if desired image-wise charging,followed either by image-wise exposure and heating, or by heatingalone,- in which process deformation is effected only in a portion ofthe layer, by using templates during charging and/or heating, andheating is performed by a dry thermal treatment. I

The term deforming a thermoplastic, preferably photoconductive layer"comprises the formation as well as the erasure or correction of adeformation image.

The deformation image is produced in the usual manner, by sprayingelectric charges, if desired in the form of an image, upon thethermoplastic layer, or, in the case of a thermoplastic photoconductivelayer, by charging, image-wise exposure, and thermal development. Theerasure ofa deformation image is performed by heat treatment. Correctionof a deformation image is effected by erasure of one image and formationof another.

For deforming a portion only of the layer, appropriate templates areused, e.g. high voltage electrodes or counter-electrodes of suitableshape for electrostatic charging, and appropriately shaped cooled orheated templates which are in contact with the recording material, forerasure. In a preferred embodiment of the invention, deformation of thelayer is performed by lines or points.

In this manner, a desired alteration of the existing information isachieved without influencing the information stored in neighboringareas.

The process of the invention for line-wise or pointwise deformation maybe applied to all types of originals and writing. It is of particularadvantage, however, for use in the micro recording field. In this field,reduction scales of 6:1 to about 30:l, and in special cases even larger,are usual. The deformation process according to the present invention isparticularly suitable for holographic recordings.

The size ofa hologram may be reduced down to areas within the range ofsquare millimeters, without substantially impairing the visibility ofthe image by the signalnoise ratio. Therefore, it is possible to storeon a recording material so-called sub-holograms in the form of smallholograms which are spaced from each other and preferably are arrangedin lines. According to the present process, it is possible toselectively insert or erase individual sub-holograms whose sizecorresponds to side lengths of a few millimeters or even fractions of amillimeter. Since a combination of methods is possible, ie to producesub-holograms by means oflaser beams in one area and insertalphanumerical characters by image-wise exposure in other areas, aneffective method is obtained for coding the holograms in such a mannerthat a certain hologram may be selected by techniques usual in themicro-recording field.

It has been found that charge images present on a thermoplastic,preferably photoconductive layer, can be converted into deformationimages by heat irradiation, e.g. by infra-red rays, withoutsubstantially influencing neighboring deformation images during thermaldevelopment. Obviously, the formation of deformation images under theinfluence of electrostatic repulsion within the charge image proceedsmuch faster than the levelling of deformation images.

According to the present invention, charges which are confined to a verynarrow zone may be applied to the thermoplastic layer by means ofelectron beams. Charging by means of a corona device is technically lessexpensive, however. For this purpose, a potential of some thousand voltsis applied to a thin wire or a comb of metal needles, so that chargesare sprayed upon the recording material lying beneath the corona, whileit is grounded from the back, either directly or via acounter-electrode.

When using this charging method, it must be taken into account whetherthe thermoplastic, preferably photoconductive layer is applied to anon-conductive supporting film, or is on an electrically conductiveintermediate layer.

The invention will be further illustrated by reference to theaccompanying drawings in which FIG. 1 illustrates the fundamentalprocesses for charging a recording material which contains noelectrically conductive intermediate layer,

FIG. 2a-2d indicate various shapes and types of templates,

FIG. 3 illustrates a process for developing or erasing deformationimages along a narrow region,

FIG. 4 illustrates an infra-red radiator for heating an area ofrecording material to be developed or erased,

FIG. 5 illustrates the fundamental process used to produce specialdeformation images on thermoplastic photoconductive surfaces on whichdeformation images are already present. In FIG. 5 the recording materialcontains no conductive intermediate layer,

FIG. 6 illustrates thermal development of the material shown in FIG. 5,

FIG. 7 illustrates contact bars for adjusting an image, and

FIG. 8 illustrates an apparatus according to the invention including aclosed, circular movement of the recording material.

FIG. 1 illustrates the fundamental process for charging a recordingmaterial which contains no electrically conductive intermediate layer. Agrounded counterelectrode template in the form of a wedge-shaped cuttingedge 4 of electroconductive material is pressed, from the back, i.e.from the support, upon the mounted recording material 1 comprising thesupport 2 and the thermoplastic photoconductive layer 3. The mountingfor the recording material, e.g. a vacuum frame pro vided with anopening in the center thereof for the counter-electrode, is not shown inthe drawing.

The recording material 1 faces a corona wire 5 which is connected to ahigh voltage source (not shown). The corona wire 5 is arranged such thatit may be displaced relative to the recording material 1 Preferably, itis located opposite to the cutting edge 4. In any case, with thisarrangement, the recording material is charged only in a narrow zonewhich is determined by the contact with the cutting edge 4. The width ofthe charging area may be reduced to a few tenths ofa millimeter. Byimage-wise exposure, a charge image may be produced within the chargingarea on the recording material and this becomes visible in the form of adeformation image during the following thermal developing process.

In order to be able to charge different areas of the recording material1, it is necessary for the wedge-shaped cutting edge 4 to be arrangedsuch that it can be moved relative to the recording material in thedirection of the arrows shown in the drawing. When performing theprocess, either the recording material 1 or the cutting edge 4 may bestationary. The various positions may be adjusted by means of micrometerscrews, for example.

The shape of the counter-electrode templates is not restricted to thatof the wedge-shaped cutting edge 4 in FIG. I, but the template may alsohave a blunt edge, as shown in FIG. 2a, when a wider area is to becharged. For point-wise charging, the counter-electrode template mayhave a cone-shaped end, as shown in FIG. 2!). When charging individuallines, a counter-electrode of such shape also may be moved during thecharging op eration. Further, it is possible for the counter-electrodetemplate to be provided with a slot (FIG. 2c) or a hole (FIG. 2d), sothat lines or points remain free from charges and no deformation imageis formed in these areas. From the types of templates shown, morecomplicated shapes may be composed, if such shapes should becomenecessary. However, the preferred shapes for the counter-electrodetemplates are those having a pointed, cone-shaped, or wedge-shaped end.

For the local charging of recording materials consisting ofthermoplastic, preferably photoconductive layers on conductivesupporting materials, or of supporting materials with a conductiveintermediate layer, on the other hand, specially shaped, possiblymovable high-voltage electrode templates must be used, which correspondin their shapes to the counter-electrodes described above.

The specially shaped high-voltage electrodes also may be used forrecording materials without electro conductive intermediate layers whencorrespondingly shaped counter-electrodes are used, or when therecording materials are simply backed by an electroconductive material.In the interest of sharper focusing, however, the system comprising ashaped high-voltage electrodes and shaped counter-electrode ispreferred.

The process steps used in the deformation process according to theinvention for the purpose of developing or erasing relief images, by adry thermal process, are the same for all recording materials described,regardless of whether they contain a photoconductor or not and are withor without an electroconductive intermediate layer. Obviously, with therecording materials of the invention, the equalization of temperaturethroughout the recording material is effected within fractions of asecond. By placing the recording material upon a template of readilyheat-conducting material, a temperature profile may be produced in therecording material even by uniform irradiation with infra-red rays, inthat the areas in contact with the template are heated to noticeablylower temperatures than the freely stretched areas. This effect may beutilized for a locally defined thermal development of charge images intodeformation images, or for the local erasure of deformation images bysmoothing them out at elevated temper ature. Therefore, irradiation withheat rays is performed while the back of the recording material is incontact with shaped templates of readily heat conducting material.

The principle of the process for developing or erasing deformationimages along a narrow region is illustrated in FIG. 3. A metal template6 provided with a slot 7 is pressed from the back upon the support of amounted recording material 1 comprising the support 2 and thethermoplastic layer 3 which carries the charge or relief image (themounting for the recording material being not shown). The metal template6 may be maintained at room temperature or it may be adjusted to anothertemperature, especially cooled. The recordingmaterial l faces a heatingwire 8 which emits infra-red radiation. Alternatively. a laminar heatingelement or other infrared radiator may be used. Further, the infra-redradiator and recording material may be either arranged such that theyare movable with respect to each other. or they may be stationary. Inany case, a deformation image is developed or erased on the recordingmaterial opposite slot 7 only.

Preferably, an infra-red radiator is employed the radiation area ofwhich is geometrically adapted to the area on the recording materialwhich is to be developed or erased. Such adaptation may be achieved by asuitably coiled heating wire or by interpolating appropriate screens.Closely coiled infra-red radiators 9 (see FIG. 4) with an ellipticalreflector 10 are particularly suitable, because in this case the emittedradiation may be focused in a particularly favorable manner.

It is also possible for the template 6 to be movable in the direction ofthe arrows (FIG. 3). The template may not only be of the slotted shapeshown in FIG. 3, but the most varied geometrical shapes and sizes arepossible. The preferred basic shapes, from which more complicatedpatterns may be formed, are templates having circular or slot-likeopenings, corresponding to the shapes indicated in FIGS. and 2d for thehigh voltage templates or counter-electrode templates.

It has been found that the area which is developed or erased, does notcorrespond to the area determined by the slot or the opening in thetemplate. In most cases, a smaller area is developed or erased, and thesize is also dependent upon the thickness of the recording materialused.

For instance, in the case of a slot of a width of 0.5 mm, the area whichis developed or erased is not 0.5 mm wide, but about 0.3 mm, when arecording material of a thickness of 40 am is used. When the recordingmaterial is 120 ,um thick, an area of about 0.45 mm is developed orerased.

In a further embodiment of the process according to the invention, thedescribed templates used for the pointed deformation by dry thermaltreatment of a recording material may be replaced by heated stampshaving the shape of the described high voltage electrodes orcounter-electrodes, the stamps being pressed from the back upon thesupport of the recording material. In this manner, it even may bepossible to eliminate the infra-red radiation. In this case, deformationtakes place only in those areas where the heated stamp is in contactwith the recording material.

Point-shaped, circular, wedge-shaped and square stamps have proved to beparticularly suitable. Stamps in the form of a planar surface haveproved to be particularly advantageous.

When it is desired to produce special deformation images onthermoplastic photoconductive surfaces on which deformation images arealready present which must be impaired, charging and developing may becombined, by charging only small areas and developing only the chargedareas by heating, after image-wise exposure. For this purpose, therecording material may be first suitably charged anditheri conveyed,after imagewise exposure, to a corresponding developing station. Caremust be taken that the charging area and the developing area correspondexactly. This difficulty may be avoided when the'position of therecording material relative to the templates is not changed duringcharging and development. In FIG. 5, the fundamental process to be usedfor recording materials containing no conductive intermediate layers isshown. The counterelectrode 4 in the form of a'wedge-shaped cutting edgeis moved in the opening of the developing, template 6, which is providedwith a slot. During charging, the counter-electrode is advanced until ittouches the back of the recording material and may be moved along therecording material I in the direction of the arrows.

At this stage, the template 6 which will; be later used for development,is retracted. During thermal development after image-wise exposure, thecounter-electrode 4 is retracted, and template 6 is advanced and touchesthe back of the recording material I, as shown in FIG. 6.

For the combined charging and development of recording materials havingan electrically conductive intermediate layer, the recording materialmay be in contact from the back with a template of suitable shape, and acorrespondingly shaped high voltage electrode template is then arrangedexactly opposite it. After charging, the high voltage electrode isremoved from the recording material.

For performing the process of the invention, an apparatus is required bywhich the'individual areas of the layer which are to be deformed can beexactly located. The apparatus contains the structural elements'normally required for the relief process, viz. mounting for therecording material, charging station, exposure station, and a stationfor dry thermal treatment. The re-- cording material executes a relativemovement with respect to the individual stations, i.e. it may travelalong a closed, e.g. circular path, or on an elongated path.

Thus, the present invention is also concerned with an apparatus forperforming the process for deforming a thermoplastic, preferablyphotoconductive layer. For electrostatic charging and/or heating,high-voltage electrode templates and counter-electrode templates, and/ordeformation templates (see numeral 4 and FIGS. 2a, 2b, 2c, and 2d) ofmaterials of good electroconductivity or heat-conductivity are provided.Coneshaped or wedge-shaped high-voltage electrode templates orcounter-electrode templates (numeral 4 and FIG. 2b) and/or deformationtemplates provided with a hole or a slot (see FIGS. 2c and 2d) arepreferred.

Heating is effected by supplying thermal energy, preferably only to theareas to be defomed. Infra-red radiators, e.g. halogen-tungsten lamps,whose effectiveness can be increased by focusing the rays, have provedto be of advantage. A closely coiled infra-red radiator 9 in combinationwith an elliptic reflector 10 (see FIG. 4) has proved to be particularlyfavorable. In addition, it is possible to remove the actinic componentsof the light by interposing a colored glass filter 11.

The devices for electrostatic charging and dry thermal treatment arearranged such that they are movable in relation to the deformableportion of the thermoplastic layer. The desired positions can bereproduceably adjusted by means of measuring instruments, such asmicrometer screws.

Two contact bars 12 and-13, which are at right angles to each other andwhosecontact separations l4 correspond to the screen width of the imagefield, are advantageously used for adjustment, as shown in FlG.7, sothat the transistion from one image field 16 to the next may correspond,e.g., to one image unit. By merans of the contact bars, an electricalcontrol is possible, so that the desired adjustment can be madeautomatically.

ln P10. 8, the apparatus according to the invention is illustrated byreference to a closed, circular movement of the recording material. Theapparatus contains a turntable 17 provided with the mounting 18 for therecording material 1, an optical system 19 for reproduction, andoriginal20, a lamp 21 with a condensor 22, and the heating station 23.

The recording material 1 is fastened to the mounting byjmeans of ametallic suction plate 24. The mounting 18, which may be, e.g., of castaluminum, may be connected to a thermostat (not shown). For deformationof the recording material, the mounting 18 with the suction plate 24 hasin its center, preferably only in one spot, a bore 25 with a fixeddiameter of, e.g., 7 mm, into which the differently shaped templates forelectrostatic charging and/or heating are fitted.

For deforming different areas of the recording material which can alsobe achieved by a relative movement between the recording material andthe templates, as described above a mounting is advantageously usedwhich is provided with a rectangular opening of larger size, e.g. ofabout X 15 mm. For electrostatic charging of a surface, a metal plug maybe inserted into this opening, which completely fills it. When onlyaportion of the area is to be charged, the metal plug is replaced by aplug of dielectric material, e.g. plexiglass, provided with ascreen-like arrangement of bores of approximately 2 mm diameter, intowhich a counter-electrode may be inserted for selective charging.

For selective heating, a metal plug is inserted which opposite tothearea to be deformed on the recording material, is provided with abore of corresponding diameter (2 mm) into which the specially shapedtemplate is inserted. Where the metal plug is in contact with therecording material, the thermal energy supplied is carried off soquickly that the recording material is not deformed in this area.

By turning the turntable, the mounting 18 carrying the recordingmaterial 11 is conveyed to the different stations required for imageformation. The turntable 17 is turned by a synchronous motor with avariable gear. The peripheral speed may be adjusted as desired. A speedof 2 cm per second, which may be increased or reduced by several steps,has proved to be advantageous.

In position 26, opposite to the corona device 27, the material ischarged, and at 28 it is image-wise exposed. In order to avoid blurringduring exposure, the drive of the turntable may be interrupted by anadjustable contact switch and the turntable stopped by an electromagnet.After a predetermined dwell at station 28, the electro-magnet releasesthe turntable and the mounting with the recording material thereon isconveyed to the thermal developing station 23 (position 29 of theturntable).

The invention will be further illustrated by the following examples:

EXAMPLE 1 20 g of polystyrene having an average molecular weight ofabout 30,000, 10 g of low molecular weight poly-a-methylstyrene, and 3 gof 2,5-bis-(p-diethylaminophenyl)-l,3,4-oxadiazole are dissolved in mlof chloroform. The resulting solution is cast upon a 50 p. thickpolyethylene terephthalate film placed on a whirler. After l0 seconds,the coated film, which is still wet, is taken from the whirler andstored for l5 minutes at room temperature unti it is dry to the touch.Finally, it is heated for 20 minutes at a temperature of 50C in acirculating air drier to remove the solvent. 7

A sample of the coated film is pressed upon a metallic suction platewhich is provided with a bore of 7 mm diameter in its center. lnto thisbore, metal templates of different shapes may be inserted which contactthe back of the coated film only during charging. The coated film ischarged by passing it at a distance of 1.5 cm and a speed of 2 cm persecond past a needle corona to which a potential of 8 kV has beenapplied.

Subsequently, the material is exposed to the light of a 200 wattprojector lamp, using an optical system of f= 35 mm. A transparentoriginal showing 8 printed lines of 2 mm height each is reproduced at ascale of reduction of l5:1.

The image is adjusted such that it is projected centrally upon the borein the suction plate. Exposure time is 10 seconds. For development, thecoated film on the suction plate is positioned at a distance of 0.5 cmfrom a 2 cm wide, 8 cm long, and 0.01 cm thick steel sheet to which avoltage of 2.8 volts is applied for 1.5 seconds. The heating power isabout 0.5 kW.

Depending on the shape of the metal template inserted into the boreduring charging, some parts of the coated film are not charged, so thatrelief images are produced in which some lines are missing. The resultsare compiled in the following Table 1:

TABLE 1 Shape of the Template (in contact during charging only) levelcircular area of a diameter of 7 mm level circular area with a slot of 1mm width level circular area with a bridge of 2 mm height and 1 mm widthEXAMPLE 2 l g of copper phthalocyanine, 5 g of low molecular weightpolymethyl styrene, and 10 g of polystyrene having an average molecularweight of about 30,000 aredissolved in 50 ml of chloroform whichcontains 1 drop of silicone oil per liter of chloroform. A 50 p. thickpolyester film carrying a 22 t thick top layer of polyvinylidenechloride is coated with this solution as described in Example 1 and thendried. Charging, exposure, and development are as described in Example1, with the exception that the metal template with the level circulararea closes the bore during charging; the exposure time is l/200seconds; and metal templates of different shapes are in contact with theback of the coated material during development. Depending on the shapeof the metal templates used. a corresponding area of the coated materialremains undeveloped during thermal development. The results are compiledin the following Table 2:

Table 2 Shape of the Template (in contact during development only) levelcircular area of a diameter of 7 mm Numbers of the Reproduced Lines (thelines are consecutively numbered from 1 to 8) (none of the lines of thecharge image are developed into a relief image) level circular area witha slit ofl mm width 5.

level circular area with a machined bridge of l 2 mm height and 1 mmwidth The same results are obtained when an electrically non-conductivelayer of indium, which increases reflection, is applied to thethermoplastic photoconductor layer at a reduced pressure of at leastTorr. before the image is produced.

EXAMPLE 3 EXAMPLE 4 A polyester film is provided with a photoconductiveThe original used for exposure is a transparent film showing a linepattern which is reproduced at a reduction scale of 15:1. Thermaldevelopment is effected as described in Example 2. after the metal pinhas been retracted through the metal template and the metal templatewith the 0.5 mm diameter bore has been advanced until it touches theback of the film. The scaleddown image of the line pattern is visible onthe film in a circular relief image of 0.28 mm diameter. When apolyester film of 100 p. thickness is used for coating. the relief imageproduced has a diameter of 0.48 mm.

EXAMPLE 6 l g of poly-N-vinyl carbazole, l g of trinitrofluorenone, 10 gof chlorinated diphenyl, and 10 g of low molecular weightpoly-a-methylstyrene are dissolved in 50 ml of tetrahydrofuran. Coatingand drying are as described in Example 1, using a polyester film as thesupport. During the charging process, the metal template with the levelcircular surface is inserted into the suction plate. During thermaldevelopment, the metal template with the slot is inserted into thesuction plate until it touches the film. During exposure, the originalis masked in such a manner that only one line is reproduced on the film.

Each time after the formation of one image, the original is displaced byone line, and the film lying on the suction plate is shifted by the samedistance. Thus, the individual lines of the original are reproduced oneafter the other on the film carrying the thermoplastic photoconductorlayer. The results are shown in Table 4 below.

Table 4 layer a d rib d i Example 1 i g 2-viny] 4 (4'- Reproduced LineLines which can be Read as Deformath b fth t' 1 th b f h l'diethylam1nophenyl)-5-(2-chlorophenyl)-l,3-oxazole f ggg gf e g g g s eH o eac me as the photoconductor. Charging 15 as described in Ex- 1 l,ample 1; exposure and development are carried 5 3 through as describedin Example 2. For the charging 40 4 l, 2, 3.4. procedure, the coronadevice is adjusted to a positive 2 j 6 potential of 8 kV. The resultsare compiled in Table 3.

Table 3 Shape of the Template Shape of the Template Number of the usedduring Charging used during Thermal Reproduced Development Lines (thelines are consecutively numbered 1 8) level circular surface levelcircular area with a slot of 1 mm with a machined l.2,3 6, width bridgeof 2 mm 7.8,

height and 1 mm width level circular area w. level circular areamachined bridge 2 mm with a slot of 1 mm 4,5,-, high and 1 mm wide widthEXAMPLE 5 EXAMPLE 7 A film consisting of a 19 11. thick polyester filmto which a thermoplastic photoconductor layer of 20 p.

thickness was applied as described in Example 2 is charged as describedin Example 1. During charging, the film rests on a suction plateprovided with an opening through which a brass bar of 7 mm diameter ispartially inserted. The brass bar has a central bore of 0.5 mm diameter.through which a metal pin with a coneshaped point is pushed until ittouches the back of the film.

A polyester film is coated as described in Example 6 and then dried, anda relief image is produced thereon by the method stated in Example l.The film carrying the relief image is placed upon the suction mountingin such a manner that the relief image is in the center of the bore.Then a metal template is inserted into the bore, which has a levelcircular surface with a 0.5 mm wide slot. The layer side of the materialis irradiated with infra-red radiation as described in Example 1. The

relief image is levelled out in the areas not in contact with thetemplate, viz. opposite the slot, whereas it is retained in all otherareas EXAMPLE 8 A polyester film is coated and dried as described inExample 2. For charging, exposure, and development, the method ofExample 1 is repeated, with a metal template being in full contact withthe back of the material during charging. A complete relief image istherefore obtained which shows 8 lines, according to the original used.In order to exchange an item of the invention recorded, e.g. a certainnumber in the present case, a metal template with a 0.5 mm bore isinserted into the suction mounting and the recording material showingthe relief image is'positioned in such a manner that the numberto bereplaced is opposite the bore. Adjustment is facilitated by using eithera mounting which is movable in-a vertical plane to the bore, or amovable metal template having a bore.

When the material is irradiated with infra-red radiation as described inExample 1, only the relief image opposite the bore is levelled. Afterthe erasing process, the recording material is charged again, with aplug being inserted into the bore in the metal template. After the newnumber has been beamed upon the material, the plug in'the bore of themetal template is retracted and the material is again irradiated withinfrared light. In the area of the erasure, a new relief image is formedwhich'shows the desired number. All other areas of the image remainunchanged.

When the new number is reproduced by this method without prior erasureof the original number, a relief image of the new number on top of aweak relief image of the original number is obtained.

EXAMPLE 9 A thermoplastic layer containing no photoconductor is producedon a polyester film according to the method stated in Example 1. Thislayer is uniformly charged as described in Example 1 and then touchedfor seconds with a metal template comprising a glass plate as thesupport and a thin metal layer thereon showing a line pattern. Thecharge image produced on the thermoplastic layer is developed into arelief image by irradiation with infra-red rays.

The film carrying the relief image is placed upon a suction mountingprovided with a bore in such a manner that the relief image facesoutwardly and is opposite the center of the bore. A metal pin of 1 mmdiameter is inserted into the bore until it touches the back of thefilm. The other end of the metal pin is insulated and a resistance wireis coiled around it to which such a voltage is applied, via anadjustable transformer, that the metal pin is heated to a temperature ofabout 75C. After about 5 minutes, the relief image has become noticeablyflatter in the vicinity of the heated metal pin. When using infra-redradiation, as is normal for development, the relief image opposite theheated metal pin may be levelled within fractions of a seco.nd, withoutvisibly damaging the relief images in the-other areas of the material. 1

EXAMPLE 10 A polyester film is coated as described in Example 2, dried,and then charged in a predetermined area by means of an electrode havinga cross-section of 1.5 to 2 mm, similarly as in Example 1. Exposure isperformed with the aid of laser light which is separated into twocomponent rays by means of a beam splitter, to'pro duce a hologram.

One of the component rays is directly beamed upon the charged recordingmaterial, and the other component ray passes a diffusing lens and theoriginal and strikes the recording material in such a manner that thetwo component rays are superimposed. The recording material is behind ashutter with an opening of 1.2 X 2 mm. After an exposure time of Isecond (He/Ne-Laser of 2 mW, T mode, diverging light) and thermaldevelopment, a relief image is obtained on which the object is visibleunder illumination with the direct component ray. With a hologram of asize of 1.2 X 2 mm, the noise does not prevent the reproduction of theimage. Further holograms are produced by the same method, except thatother areas of the recording material are charged, exposed, anddeveloped.

It will be obvious to those skilled in the art that many modificationsmay be made within the scope of the present invention without departingfrom the spirit thereof, and the invention includes allsuchmodifications.

What is claimed is:

1. In the process for deforming only a selected area of an image on athermoplastic layer applied to a supporting film by heating saidthermoplastic,

the improvement which comprises non-selectively heating thethermoplastic layer from the front by dry thermal treatment andsimultaneously contacting the supporting film in the back of thenonselected area with a material having an even surface and good heatconductivity.

2. A process according to claim 1 in which heating is effected in aselected area bearing an electrostatic image.

3. A process according to claim 1 in which heating is effected in aselected area bearing a deformation image.

4. A process according to claim 1 in which the thremoplastic layer isphotoconductive.

5. A process according to claim 1 in which the supporting film isnon-electroconductive.

6. A process according to claim 1 in which deformation is effected inpointor line-wise areas.

7. A process according to claim 1 in which deformation is effected onmicro cards.

8. A process according to claim 1 in which deformation is effected onholograms.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. 33,897,247

.DATED I Iuly 29, 1975 I Gunther Schadlich et al It is certified thaterror appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

Column 5 line 64, after "must" insert not Column 7, line 6, "merans"should read means Column 8, line 64, "seconds" should read second Column12, line 36, after "thermoplastic" insert layer Signed and Sealed this[SEAL] I y-fif D3) 0f November 1975 A ttest:

:33! c. (lia son c. MARSHALL DANN mg jjlcer Commissioner of Patents andTrademarks UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENTNO. 1 3,897,247

DATED Iuly 29, 1975 INVENTOR( Gunther Schadlich et al It is certifiedthat error appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

Column 5, line 64, after "must" insert not Column 7, line 6, "merans"should read means Column 8, line 64, "seconds" should read second Column12, line 36, after "thermoplastic insert layer Signed and Scaled thisArrest:

RUTH C. MASON C. MARSH Attexting Offi ALL DANN Commissioner oj'Parentsand Trademarks

1. IN THE PROCESS FOR DEFORMING ONLY A SELECTED AREA OF AN IMAGE ON ATHERMOPLASTIC LAYER APPLIED TO A SUPPORTING FILM BY HEATING SAIDTHERMOPLASTIC, THE IMPROVEMENT WHICH COMPRISES NON-SELECTIVELY HEATINGTHE THERMOPLASTIC LAYER FROM THE FRONT BY DRY THERMAL TREATMENT ANDSIMULTANEOUSLY CONTACTING THE SUPPORTING FILM IN THE BACK OF THENON-SELECTED AREA WITH A MATERIAL HAVING AN EVEN SURFACE AND GOOD HEATCONDUCTIVITY.
 2. A process according to claim 1 in which heating iseffected in a selected area bearing an electrostatic image.
 3. A processaccording to claim 1 in which heating is effected in a selected areabearing a deformation image.
 4. A process according to claim 1 in whichthe thremoplastic layer is photoconductive.
 5. A process according toclaim 1 in which the supporting film is non-electroconductive.
 6. Aprocess according to claim 1 in which deformation is effected in point-or line-wise areas.
 7. A process according to claim 1 in whichdeformation is effected on micro cards.
 8. A process according to claim1 in which deformation is effected on holograms.